Various cloud service hosting solutions are available to customers, such as public clouds, private clouds, and hybrid clouds. Public or shared clouds allow customers to provide services to users over a network, such as the Internet, an intranet, or other public or private data network, with little or no control over the underlying technology infrastructure. Public clouds offer customers reduced complexity in testing and deploying new services. Private or enterprise clouds are deployed over a company intranet or hosted datacenter and offer private services for a company or organization. Private clouds may provide security, availability, or fault-tolerant solutions that are not possible in a public cloud because the private cloud typically does not share resources with other organizations. Hybrid clouds provide an integrated approach that combines the power of both public and private clouds. Customized rules and policies may be used to allocate activities and tasks to internal or external clouds as needed.
Each cloud type—public, private, or hybrid—may be used to provide different service types. Software-as-a-Service (SaaS) provides a specific service, such as an email service or a data center service, which is hosted on the cloud and allows end users to access the service over the Internet. Platform-as-a-Service (PaaS) provides a programmable environment where code can be deployed, which allows customers to deploy their applications in the cloud without having to manage the server infrastructure. Infrastructure-as-a-Service (IaaS) provides customers with maximum interaction with the underlying server infrastructure. IaaS customers rent the hardware, such as servers, load balancers, firewalls, and cables, and configure them remotely with their own solutions.
Cloud service providers offer customers the ability to provision new virtual machines as needed. However, this process is cumbersome because it takes time, requires many different APIs to be called to manage operating systems and application images. For example, the customer must determine what bandwidth is required for a service, and then determine what virtual machine resources are needed to support that bandwidth under desired service-level agreements (SLA). The customer must understand the virtual machines capabilities and then deploy and manage the virtual machines. This requires specialized knowledge and resources that may be outside the customer's capabilities.